Greenhouse control systems are vital to commercial horticulture, vertical farms, plant science research and a variety of other controlled-environment agriculture applications. They enable growers to automate and precisely control conditions in their facilities so that plants can thrive in their indoor environments. As greenhouse technologies become more advanced and complex, control systems have become essential for managing the many aspects of operating them successfully.
From simpler setups to advanced, integrated greenhouse control systems, the options are varied and must be carefully considered. This Insight will answer some important questions and considerations for growers as they select a control system for their facilities, including:
- What is a greenhouse control system?
- How do they work and what functions do they control?
- Why are they important to greenhouse operations?
- What is the difference between basic and advanced control systems?
- How do you choose the right control system for your needs?
Knowing the answers to these questions will help you select a control system aligned with your current operations and goals while maximizing your ROI on the system you choose.
Quick Takeaways:
- Greenhouse control systems automate key environmental processes, enhancing the efficiency and consistency of plant growth.
- Advanced systems offer integrated control over temperature, lighting, irrigation, humidity and CO2 control, ensuring optimal conditions for various crops.
- Scalability and customization are crucial factors when selecting a greenhouse control system, allowing it to adapt to future growth and changing needs.
- Data logging in advanced systems provides valuable insights, enabling growers to refine operations and replicate successful strategies.
- Choosing the right system depends on the size of the greenhouse, crop requirements, desired automation level, and local environmental conditions.
What is a Greenhouse Control System?
A greenhouse control system is designed to automate and manage the various environmental factors within a greenhouse to create an optimal growing environment for plants. They ensure that the repeatable processes that can and should be automated (temperature, lighting, irrigation, humidity and CO2) are handled accordingly.
In turn, growers can focus more on growing and less on managing the environment. Greenhouse control systems provide more efficient, real-time greenhouse management because they don’t require the extra time and risk of human error that comes with manual adjustments. In turn, greenhouses operate more smoothly and provide more stable environments for plants growing inside them.
Control systems vary in complexity, from basic setups to highly sophisticated systems:
- Basic Thermostats: Typically control temperature only by turning heating or cooling devices on or off as needed
- Step Controllers: Offer more control than basic thermostats by allowing for staged temperature adjustments, and can manage heating and cooling in increments, turning on or off equipment as the need for temperature adjustment changes
- Programmable Logic Controllers (PLCs): Provide a higher level of control by allowing growers to automate and manage multiple aspects of the greenhouse environment. PLCs can be programmed to control temperature, humidity, and ventilation based on specific parameters and sequences
- Integrated Control Systems: Manage all aspects of the greenhouse environment by coordinating the operation of heating, cooling, ventilation, CO2, lighting, and irrigation, and making adjustments in real time based on sensor data
When considering these types of greenhouse control systems and which is best to choose, many facility managers wonder if their building management system can handle their greenhouse control needs. There is one key reason this isn’t the right approach: Building management systems are people-centric, while greenhouse control systems are plant-centric.
Attempts to transfer the capabilities of a building management system to a greenhouse environment lead to issues with the system not understanding desired conditions, and thus an inability or inconsistency to create them.
For example: Building management systems are designed to maintain temperature and humidity levels in insulated structures within parameters ideal for humans. They are typically incapable of managing the fast-changing and dynamic environments of greenhouses and therefore tend to maintain poor control of temperature and humidity which leads to sub-optimal uniformity and plant development.
Key Functions of a Greenhouse Control System
As they automate and streamline greenhouse operations and environmental conditions, control systems have a few key areas of focus. These include:
Temperature Management
Greenhouse control systems are crucial for managing temperature by automating heating and cooling processes to maintain a stable environment within the greenhouse. Simpler systems use basic thermostats or step controllers to turn heating and cooling equipment on and off as needed. Advanced systems integrate multiple control mechanisms for more nuanced temperature management.
Advanced systems can stage heating, incrementally increasing or decreasing temperatures to avoid abrupt changes. They can coordinate various equipment, such as heaters, fans, and vents, to maintain an optimal climate, adjusting in real-time to environmental changes inside and outside the greenhouse.
Lighting Control
Controlling light intensity is critical to photosynthesis in greenhouse environments. Greenhouse control systems manage lighting by adjusting the intensity, duration, and spectrum to meet the specific needs of different crops.
Advanced systems have the capability to control not only the timing of the lights but also the quality of light, including spectrum adjustments such as red, far-red, blue, and white light. This fine-tuned control ensures that plants receive the exact type and amount of light needed for each growth stage.
In addition to basic on/off functionality, higher-end control systems can dynamically adjust lighting based on real-time conditions inside the greenhouse. For example, they can measure the amount of natural light available and automatically supplement it with artificial lighting as needed. This helps to maximize energy efficiency while ensuring that plants receive the light quantity they need that day.
Water & Irrigation Management
Greenhouse control systems automate irrigation processes by adjusting watering schedules based on several factors, including light levels and the specific growth stages of the plants. Basic systems operate on a simple timer, turning irrigation systems on and off at set intervals. Advanced greenhouse control systems can synchronize irrigation with the amount of light the plants receive.
Advanced systems also offer integration with fertigation setups, allowing nutrients to be delivered along with water. This integration ensures that plants receive a balanced supply of both water and nutrients at the correct times. They can incorporate soil moisture sensors to provide real-time feedback, further enhancing irrigation precision.
Humidity Control
Managing humidity is essential in a greenhouse environment to prevent plant diseases and ensure proper transpiration rates. Greenhouse control systems achieve this by coordinating ventilation, heating, and dehumidification processes.
Simpler systems rely on basic ventilation strategies, such as opening vents to allow humid air to escape and bringing in fresh air. This approach, however, can inadvertently affect temperature as the external air might be cooler or warmer than desired.
Advanced greenhouse control systems integrate multiple processes to more effectively control humidity. They intelligently adjust heating to increase the air's capacity to hold moisture before venting it out, which helps to reduce humidity more efficiently.
CO2 Control
Supplying extra carbon dioxide to many greenhouse crops is a common method used for increasing the crop’s capacity to grow. Plants use photosynthesis to create the energy that they need to grow. Light and CO2 play a major role in photosynthetic activity, and advanced control systems have programs designed to take into consideration various environmental factors that play a role in determining how much CO2 should be supplemented, accurately control the equipment that provides the CO2, and monitor the CO2 levels to ensure targets are met. Advanced control systems also have the ability to set off alarms if CO2 levels get too high, as this condition can be extremely hazardous to humans.
Choosing the Right Greenhouse Control System
When selecting the right greenhouse control system for your operation, consider the following:
Size and Type of Greenhouse
The size and complexity of your greenhouse are important for determining the appropriate control system for your facility. Larger or more complex greenhouses often require advanced systems that can integrate multiple environmental controls.
On the other hand, smaller greenhouses or simpler operations may be satisfied with a basic system to handle essential functions without extensive customization.
Types of Crops Being Grown
Different crops have specific environmental needs that must be met for optimal growth. For example: Some crops may require precise temperature and humidity controls, while others might need very specific lighting conditions. The control system you choose should be capable of addressing the unique requirements of the crops you plan to grow.
Scalability Needs
If you anticipate expanding your greenhouse or changing the types of crops you grow in the future, scalability should be a key consideration. A scalable greenhouse control system allows for the addition of new features or capabilities as your operation grows. This makes it more cost-effective as a long-term investment because it can adapt to your changing needs without requiring a complete overhaul.
Desired Level of Automation & Control
The level of automation and control you want in your greenhouse is an important factor in choosing the right system. Some growers prefer systems automating most processes, freeing them up to focus on other aspects of their operation. Others might want more manual control over environmental factors in their facility.
Consider how hands-on you want to be with managing your greenhouse environment and choose a system that aligns with your preferred level of involvement and available time resources.
Environmental Factors & Location
The local environment and location of your greenhouse play a role in selecting the right control system. For example: Greenhouses in regions with high humidity may struggle with certain cooling methods, such as pad and fan systems, making them less effective.
Similarly, the amount of natural light, prevailing winds, and typical temperature ranges should influence your choice of equipment and control strategies. Understanding the specific environmental challenges of your location will help determine whether a basic or advanced system is more suitable for your needs.
In Conclusion
Choosing the right greenhouse control system is essential for managing a successful greenhouse facility, maintaining it efficiently and effectively, and evolving it as your operational needs change. This Insight entry covered the foundational features and functions of a greenhouse control system and how to determine what kind of system is right for your facility.
Stay tuned for part two of this series for a deeper exploration of the features offered by advanced, integrated greenhouse control systems and how they can enhance your operations and outcomes.